Enhancing Dispersion of TiB₂ Nanoparticles in Al Composites via Ultrasonic-Assisted Fast Cooling Schemes

Particle agglomeration poses the principal challenge in the solidification of particulate-reinforced metal matrix composites (MMNCs). Here, we present an approach aimed at achieving a uniform dispersing of nanoparticles (NPs) in an aluminum matrix via ultrasonic-assisted fast cooling schemes. Microstructure analysis reveals that the distribution of NPs in the matrix transforms from intergranular distribution to intragranular distribution at the microscale and the interface between NP and the matrix changes from incoherent to coherent at the nanoscale under the action of ultrasonic melt treatment. Theoretical analysis underscores the significance of NP size and cooling rate as the two prominent factors influencing NP distribution during the solidification of nanocomposites. Through the ultrasonic dispersion of NPs and particle engulfment during the fast cooling process, the ductility of highly dispersed nanocomposites exhibits significant enhancement, with an increase of 82.7 and 18.4 pct compared to that of pure aluminum and non-ultrasonic-treated samples, respectively.